U.S. Pat. No. 6,800,051 B2 and U.S. Pat. No. 4,008,850 and US 2009/0159192 A1 respectively disclose a method for making a bag having a staggered end also known as a stepped end.
US 2009/0159192 A1 discloses a perforation line in a web of tubular film, along which perforation line a segment is severed from the web of tubular film to form a staggered end. The perforation line is formed in a flat web of film, after which the tubular film is formed by folding side parts so as to overlap, and then simultaneously inserting the side folds and affixing a longitudinal center weld. Scoring apparatus are disclosed in U.S. Pat. No. 4,273,550 and U.S. Pat. No. 5,840,002 to make creases in the film for folding the film.
US 2010/0029455 A1 discloses a fabric having a layer of woven plastic bands and at least one additional material layer, and the cutting capacity of a laser can be adjusted to a thickness of the material layers to provide a perforation line.
A perforation line in a flat web of film is unsuited for a tube. Instead of manufacturing a flat web of film having a perforation line, a continuous tube without a perforation line can be manufactured at a high production speed, followed by cutting the tube to a desired length at the high production speed. The tube can be seamless. Alternatively, the tube can have one or more longitudinal seams as disclosed by Coating Excellence LLC in US 20080187695 A1, U.S. application Ser. No. 12/019,407, filed Jan. 24, 2008. Then it would be desirable to manufacture a stepped end on the tube, wherein the stepped end is adapted to be closed to make a bag. However, a tube does not encompass a flat web of film. It follows, It would be desirable to manufacture a staggered end, also known as a stepped end, on a tube, in order to take advantage of high speed manufacture of the tube.